66 BUSH DAYS 



not leave the continent. But there is another class of birds 

 that also spend the summer with us, but go far north across 

 the world to build in the northern spring. This class includes 

 some of the best-known of our birds, amongst them the swifts, 

 which may be seen on summer evenings circling round in the 

 upper air in search of insects. Though most of us are familiar 

 with the long sickle-shaped wings and graceful flight of the 

 swifts, but few of us know that these same birds, which are 

 better known to us than many Australian forms, are really 

 aliens, and have travelled thousands of miles from their birth- 

 places. The two species, the spine-tailed swift and the vvhite- 

 rumped swift, are often seen in company throughout Aus- 

 tralia and Tasmania, but while the first-named builds in Japan, 

 the latter travels on to Central Siberia. The flight of these 

 birds is amongst the marvels of natural history, and the dis- 

 tance that seems so awe-inspiring to us, is no more than a 

 few beats of the wing to them. There is no authentic record 

 of their resting in Australia, but they seem to be possessed of 

 tireless energy, and, according to Gould, the great bird 

 observer, think nothing of breakfasting in New South \\ales 

 and lunching in Tasmania. 



With such powers of speed and ever soaring flight, it is 

 easy to believe that the swifts have come from " far beyond the 

 horizon's rim " ; but it needs more imagination to realise as 

 globe-trotters the birds w^e are accustomed to see walking 

 slowly and sedately upon t*he ground. And yet of the forty- 



